diff --git a/frontend/src/admin/AdminDialogs.vue b/frontend/src/admin/AdminDialogs.vue
index 6504262..891a21e 100644
--- a/frontend/src/admin/AdminDialogs.vue
+++ b/frontend/src/admin/AdminDialogs.vue
@@ -68,8 +68,11 @@ const LIST_VALIDATION = { origins: 'originValidation', related_origins: 'related
 function addEntry(field) {
   const d = props.dialog?.data
   if (!d) return
-  // Prefill the in-domain list with the rp-id; related domains start blank
-  d[field].push(field === 'origins' ? realmRpId.value : '')
+  // Prefill the in-domain list: with the origin the admin is currently on
+  // when editing that very domain (so saving never locks them out), else
+  // with the rp-id (https default). Related domains start blank.
+  const onThisDomain = authStore.settings?.rp_id && d.rp_id === authStore.settings.rp_id
+  d[field].push(field === 'origins' ? (onThisDomain ? window.location.origin : realmRpId.value) : '')
   d[LIST_VALIDATION[field]].push(null)
   const i = d[field].length - 1
   if (d[field][i]) validateEntry(field, i)